Researchers published the first set of reports on the second Mars rover, Opportunity,
in Science on Dec. 3. Below are some images from the rover's Pancam.

Opportunity
found some of the first evidence of water on Mars in "blueberries,"
tiny hematite concretions that may have been deposited in shallow-water
environments. This close-up image of the blueberries blanketing the ripples
and troughs in the Meridiani Planum is an enhanced natural-color Pancam
photograph.